Neurogenic changes in myasthenia gravis

Twelve consecutive cases of myasthenia gravis have been studied histologically and histochemically. In addition 8 of these were studied ultramicroscopically, and 7 had nerve terminal and end-plate studies. Eleven of the cases show evidence of one type or another which supports a primary neuropathic aetiology. These findings are in keeping with some recent publications which have been reviewed.S. Afr. Med. J., 48, 1783 (1974

A structure-function analysis of the left ventricle

This study presents a structure-function analysis of the mammalian left ventricle and examines the performance of the cardiac capillary network, mitochondria, and myofibrils at rest and during simulated heavy exercise. Left ventricular external mechanical work rate was calculated from cardiac output and systemic mean arterial blood pressure in resting sheep (Ovis aries; n = 4) and goats (Capra hircus; n = 4) under mild sedation, followed by perfusion-fixation of the left ventricle and quantification of the cardiac capillary-tissue geometry and cardiomyocyte ultrastructure. The investigation was then extended to heavy exercise by increasing cardiac work according to published hemodynamics of sheep and goats performing sustained treadmill exercise. Left ventricular work rate averaged 0.017 W/cm3 of tissue at rest and was estimated to increase to ∼0.060 W/cm3 during heavy exercise. According to an oxygen transport model we applied to the left ventricular tissue, we predicted that oxygen consumption increases from 195 nmol O2·s-1·cm-3 of tissue at rest to ∼600 nmol O2·s-1·cm-3 during heavy exercise, which is within 90% of the oxygen demand rate and consistent with work remaining predominantly aerobic. Mitochondria represent 21-22% of cardiomyocyte volume and consume oxygen at a rate of 1,150 nmol O2·s-1·cm-3 of mitochondria at rest and ∼3,600 nmol O2·s-1·cm-3 during heavy exercise, which is within 80% of maximum in vitro rates and consistent with mitochondria operating near their functional limits. Myofibrils represent 65-66% of cardiomyocyte volume, and according to a Laplacian model of the left ventricular chamber, generate peak fiber tensions in the range of 50 to 70 kPa at rest and during heavy exercise, which is less than maximum tension of isolated cardiac tissue (120-140 kPa) and is explained by an apparent reserve capacity for tension development built into the left ventricle.This research was supported by an Australian Research Council Discovery Project Award to R. S. Seymour, S. K. Maloney, and A. P. Farrell (DP-120102081). E. P. Snelling holds a South African Claude Leon Foundation Postdoctoral Fellowship. J. E. F. Green is supported by an Australian Research Council Discovery Early Career Researcher Award (DE- 130100031). A. P. Farrell holds a Canada Research Chair and is supported by a Discovery Grant from the Natural Sciences and Engineering Research Council of Canada.http://jap.physiology.org2017-10-31hb2017Paraclinical Science

Rheumatoid arthritis impacts on the independent relationships between circulating adiponectin concentrations and cardiovascular metabolic risk,”Mediators of Inflammation, vol

Adiponectin and leptin are likely involved in the pathophysiology of rheumatoid arthritis (RA) and therefore potential new therapeutic targets. Adiponectin inhibition could be expected to enhance cardiovascular metabolic risk. However, it is unknown whether RA changes the influence of adipokines on cardiovascular metabolic risk. We determined whether RA impacts on the independent relationships of circulating leptin and adiponectin concentrations with cardiovascular risk factors and carotid intimamedia thickness (cIMT) in 277 black African subjects from a developing population; 119 had RA. RA impacted on the relationships of adiponectin concentrations with lipid concentrations and blood pressure, independent of confounders including adiposity (interaction < 0.05). This translated into an association of adiponectin concentrations with more favorable lipid variables including HDL cholesterol ( = 0.0005), non-HDL cholesterol ( = 0.007), and triglyceride ( = 0.005) concentrations, total cholesterol-HDL cholesterol ( = 0.0002) and triglycerides-HDL cholesterol ( = 0.0003) ratios, and higher systolic ( = 0.0006), diastolic ( = 0.0004), and mean blood pressure ( = 0.0007) in RA but not non-RA subjects. Leptin was not associated with metabolic risk after adjustment for adiposity. The cIMT did not differ by RA status, and adipokine concentrations were unrelated to atherosclerosis. This study suggests that leptin and adiponectin inhibition may not alter overall cardiovascular risk and disease in RA

Rheumatoid Arthritis Impacts on the Independent Relationships between Circulating Adiponectin Concentrations and Cardiovascular Metabolic Risk

Adiponectin and leptin are likely involved in the pathophysiology of rheumatoid arthritis (RA) and therefore potential new therapeutic targets. Adiponectin inhibition could be expected to enhance cardiovascular metabolic risk. However, it is unknown whether RA changes the influence of adipokines on cardiovascular metabolic risk. We determined whether RA impacts on the independent relationships of circulating leptin and adiponectin concentrations with cardiovascular risk factors and carotid intima-media thickness (cIMT) in 277 black African subjects from a developing population; 119 had RA. RA impacted on the relationships of adiponectin concentrations with lipid concentrations and blood pressure, independent of confounders including adiposity (interaction P<0.05). This translated into an association of adiponectin concentrations with more favorable lipid variables including HDL cholesterol (P=0.0005), non-HDL cholesterol (P=0.007), and triglyceride (P=0.005) concentrations, total cholesterol-HDL cholesterol (P=0.0002) and triglycerides-HDL cholesterol (P=0.0003) ratios, and higher systolic (P=0.0006), diastolic (P=0.0004), and mean blood pressure (P=0.0007) in RA but not non-RA subjects. Leptin was not associated with metabolic risk after adjustment for adiposity. The cIMT did not differ by RA status, and adipokine concentrations were unrelated to atherosclerosis. This study suggests that leptin and adiponectin inhibition may not alter overall cardiovascular risk and disease in RA

The reliability of physiological responses obtained during a simulated long distance triathlon laboratory test

The aim of this study was to investigate the reliability of a newly developed long distance (LD) simulated triathlon for testing performance and physiological changes in LD triathletes. Ten trained LD triathletes (mean ± standard deviation: age 34.1 ± 5.0 years, body mass 69.07 ± 13.89 kg) completed two separate trials of a simulated LD triathlon consisting of a 1500 m swim, a 60 minute cycle at 60% of power at VO2max and a 20 minute run at 70% of velocity at VO2max. Performance (time, pace, power and rating of perceived exertion) and physiological (economy of movement (oxygen cost and energy consumption), blood lactate and heart rate)variables were measured throughout the simulated LD triathlon. Coefficient of variations (CV %) and intra class correlation coefficients (ICC) were calculated to determine reliability. The current study displayed a high level of reliability, with moderate to excellent ICC measurements for performance and physiological variables (ICC 0.62 – 0.99). All physiological variables, except blood lactate, demonstrated CV values \u3c 10%. In conclusion, the newly developed LD simulated triathlon has a high level of task representation for LD triathletes and can accurately assess performance changes in a research setting

A structure-function analysis of the left ventricle

Les Anglo-Saxons figurent dans les chroniques bretonnes de la fin du Moyen Âge sous une forme très négative, incarnant l’archétype de l’ennemi héréditaire. Les auteurs, qui reprennent le récit de Geoffroy de Monmouth, les jugent responsables de la perte de l’île de Bretagne et dressent un portrait discriminatoire, presque caricatural. Les Saxons sont d’abord perçus comme des étrangers, notion qui suggère la différence et le danger, au point que le terme même de « Saxon » devient une insulte à part entière. Cette construction littéraire est plus qu’un simple réflexe xénophobe. Elle participe à l’affirmation nationale en justifiant l’ancrage en Armorique et en glorifiant les Bretons, véritable peuple martyr luttant contre l’envahisseur.In the Breton chronicles of the late Middle-Ages, the Anglo-Saxons are negatively depicted as the archetype of a hereditary enemy. Taking up Geoffrey of Monmouth’s story, the authors hold them responsible for the loss of the British island and paint a discriminatory and almost caricatured picture of them. The Saxons are so much seen as aliens, a term synonymous with difference and danger, that even the word “Saxon” becomes an insult in itself. More than just a xenophobic reaction, that litterary construction contributes towards the national assertion by justifying their settlement in Armorica and by extolling the Bretons as a truly martyred nation struggling against the invaders